Ion scale nonlinear interaction triggered by disparate scale electron temperature gradient mode

Chanho Moon, Tatsuya Kobayashi, Kimitaka Itoh, Rikizo Hatakeyama, Toshiro Kaneko

Research output: Contribution to journalArticle

Abstract

We have observed that the disparate scale nonlinear interactions between the high-frequency (∼0.4 MHz) electron temperature gradient (ETG) mode and the ion-scale low-frequency fluctuations (∼kHz) were enhanced when the amplitude of the ETG mode exceeded a certain threshold. The dynamics of nonlinear coupling between the ETG mode and the drift wave (DW) mode has already been reported [C. Moon, T. Kaneko, and R. Hatakeyama, Phys. Rev. Lett. (2013)]. Here, we have newly observed that another low-frequency fluctuation with f ≃ 3.6 kHz, i.e., the flute mode, was enhanced, corresponding to the saturation of the DW mode growth. Specifically, the bicoherence between the flute mode and the DW mode reaches a significant level when the ∇Te/Te strength exceeded 0.54 cm-1. Thus, it is shown that the ETG mode energy was transferred to the DW mode, and then the energy was ultimately transferred to the flute mode, which was triggered by the disparate scale nonlinear interactions between the ETG and ion-scale low-frequency modes.

Original languageEnglish
Article number052301
JournalPhysics of Plasmas
Volume22
Issue number5
DOIs
Publication statusPublished - May 1 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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